Bovine dominant follicular fluid promotes the in vitro development of goat preantral follicles

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Characterization of Staphylococcus aureus isolates in milk and the milking environment from small-scale dairy farms of São Paulo, Brazil, using pulsed-field gel electrophoresis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Gastrointestinal parasites occurrence in dairy cows kept in organic and conventional production system

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Pyrethroid residues in milk and blood of dairy cows following single topical applications

The presence of the pyrethroid insecticides flumethrin, deltamethrin, cypermethrin and cyhalothrin in milk and blood of 10 cows was determined after single dermal applications of recommended doses. Milk and blood samples were collected every 7 days over a 35 d period and analyzed by high performance liquid chromatography. The highest residues in milk were found on day 28 for flumethrin and day 1 for deltamethrin, cypermethrin and cyhalothrin, while in blood the highest concentrations were present on day 28 for flumethrin and deltamethrin, the first day for cypermethrin, and day 14 for cyhalothrin.

HPLC determination of flumethrin, deltamethrin, cypermethrin, and cyhalothrin residues in the milk and blood of lactating dairy cows

A procedure to determine residue concentrations of synthetic pyrethroid insecticides (flumethrin, deltamethrin, cypermethrin and cyhalothrin) in the milk and blood of lactating dairy cows was developed. Extraction was performed with acetonitrile, n-hexane partitioning, and silica gel column cleanup with n-hexane and diethyl ether. Analysis was carried out by high- performance liquid chromatography and ultraviolet detection. Recovery of the four pyrethroids averaged 78 to 91% with a minimum detectable concentration of 0.001 mg/kg. The method was reproducible and sensitive.

Evaluation of plasma membrane integrity of frozen-thawed goat spermatozoa with or without seminal plasma

The aim of the present work was to evaluate plasma membrane integrity, motility, vigor and morphology of fresh and frozen goat spermatozoa with or without seminal plasma. Semen samples were diluted in Tris solution, before and after thawing, with a combination of carboxifluorescein diacetate and propidium iodide. The results showed differences (P < 0.01) for motility and minor defects in the presence or absence of seminal plasma, for both fresh and frozen samples. Periods of collection had a significant effect on motility, probably due to changes in the photoperiod. Plasma membrane integrity was significantly reduced by the freezing process, whether seminal plasma was present or absent. In conclusion, removal of seminal plasma decreased motility and vigor rates in frozen samples. The photoperiod probably decreased the testosterone level, contributing negatively to the high percentage of sperm abnormalities, mainly damaged membranes. The use of fluorescent probes allowed a better estimation of the percentage of functional cells, instead of only estimating the percentage of motile cells or morphology defects. © 2001 Elsevier Science B.V. All rights reserved.

Efeito de estratégia de suplementação com concentrado no desempenho de cabras mestiças Saanen, em dois sistemas de produção

The experiment was carried out to evaluate the performances of cross breed Saanen dairy goats submitted to two strategies of supplementation with concentrate 30% of daily requirements in net energy (NRC, 1981) supplied by concentrate, from third week until the end of lactation (ESC. 1) or 60% of requirements from the 3rd to the 13th week of lactation and 15% from 14th until the end of lactation (ESC.2); and evaluate the animal response to these strategies of supplementation with concentrate in a semi-confined or pasture systems. Thirty one animals were used in a completely randomized design. The system of production affected the total intake of concentrate and total milk production; at pasture system the values for these two variables were higher. The supplementation with concentrate affected the total intake of concentrate and total production of milk and the relation of milk/consumption of concentrate. The highest value for relation of milk/consumption of concentrate and the least for the total consumption of concentrate were obtained at ESC. 1. Body weight affected of the system of production, resulting in a higher value to the system of pasture. Weight and body condition had different responses to he supplementation with concentrate according to the system of production. The semi-confined system ESC.2 resulted in a higher value to the body condition; the body weight was no affected. At pasture system the highest values for weight and body condition were obtained in the supplementation with concentrate ESC. 1. Reproductive parameters did not affect supplementation with concentrate and system of production.

Acute reduction in serum progesterone concentrations after feed intake in dairy cows

This study tested the hypothesis that high feed consumption will acutely decrease circulating progesterone concentrations. In the first experiment, a Latin Square design was used to test whether feeding pattern would alter circulating progesterone in pregnant lactating Holstein cows (n = 12). Feed was removed for 12 h before the experiment and cows were then either fed 100% of the total mixed ration (TMR), 50% of TMR every 12 h, 25% of TMR every 6 h, or left unfed for an additional 12 h. Blood samples were taken every hour for 24 h. Provision of 100 or 50% of TMR decreased circulating progesterone by 1 h after feeding and progesterone remained depressed until 8-9 h after feeding. Feeding 25% of TMR did not reduce circulating progesterone concentrations. Experiment 2 used a crossover design to measure the effect of acute feeding on circulating progesterone and LH concentrations during delivery of a constant amount of exogenous progesterone (Eazi-Breed CIDRs) in lactating Holstein cows (n = 8) and nonpregnant dry Holstein cows (n = 6). Blood samples were taken every 15 min for 8 h. There was no change in serum progesterone during the 8 h treatment period in unfed cows; however, feeding decreased (P < 0.05) circulating progesterone between 2 and 6 h after feeding. In lactating cows, feeding increased mean LH (P < 0.05). There were more LH pulses (P = 0.01) in lactating than nonlactating cows. Thus, acute feeding reduced circulating progesterone in pregnant lactating cows apparently due to an increase in progesterone metabolism. Interestingly, feeding multiple smaller meals eliminated the acute effect of feeding on circulating progesterone. © 2003 Published by Elsevier B.V.

Soroprevalência de Toxoplasma gondii em rebanhos caprinos no Estado de São Paulo

Four hundred forty-two serum samples were collected from dairy goats in seven regions of São Paulo State. These were tested for Toxoplasma gondii antibodies using the indirect immunofluorescent antibody test. Sixty-four (14,5%) serologically positive animals were found from all these goat farms studied.